<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>flex</title>
    <style>
      section {
        display: flex;
      }

      section > div {
        width: 100px;
        height: 100px;
        border: 1px solid #000;
      }

      .box1 {
        display: flex;
        flex-flow: column nowrap;
      }
      .box1 > div {
        width: 100px;
        height: 25%;
        flex-shrink: 0;
      }
      .box2 {
        display: flex;
        flex-flow: row wrap;
      }
      .box2 > div {
        width: 48px;
        height: 48px;
        border: 1px solid;
      }

      .box3 {
        display: flex;
      }

      .box3 > div {
        flex: 33px;
      }
    </style>
  </head>
  <body>
    <section>
      <div class="box1">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="box2">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div class="box3">
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div></div>
    </section>
  </body>
</html>
